When the Republican Party convened in Cleveland in July to nominate Donald Trump for president, Fox News was led by Chairman Roger Ailes and the prime-time lineup of Greta Van Susteren, Bill O’Reilly, Megyn Kelly and Sean Hannity.

Nine months later, only Hannity remains. According to a New York magazine report Wednesday, O’Reilly is being forced out. Matt Drudge put the reported shake-up in perspective, with characteristic subtlety:

A once-unthinkable move had begun to seem inevitable. Multiple news outlets, including the Rupert Murdoch-owned Wall Street Journal, reported Tuesday night that Fox News was preparing to sack the King of Cable News, as advertisers fled his top-rated program in response to a New York Times report that O’Reilly and the network have paid $13 million to five women over the years to settle claims of sexual harassment and inappropriate conduct. Murdoch also owns Fox News.

Earlier Tuesday, attorney Lisa Bloom said she had taken the case of a sixth woman who claims O’Reilly sexually harassed her.

Amid turmoil, Fox News has remained a ratings juggernaut. In the first quarter of this year, the network averaged 2.7 million viewers between 7 p.m. and 11 p.m., double the viewership of second-place MSNBC. The newcomers have fared particularly well. Martha MacCallum, in Van Susteren’s old time slot, delivered Fox News’s most-watched quarter ever at 7 p.m. Tucker Carlson, who replaced Kelly, did the same in the 9 p.m. hour.

But how many more changes can Fox News withstand?

Van Susteren and Kelly were popular, but O’Reilly is in another class. He has been the face of the network since its launch in 1996 and the most-watched cable news host 15 years in a row.

Even the cloud of sexual harassment had not darkened O’Reilly’s ratings; in fact, he was enjoying a boost in viewership before signing off last Tuesday for what he described as a long-planned vacation. He was scheduled to return Monday.

O’Reilly’s fill-ins — Dana Perino, Eric Bolling and Greg Gutfeld — have drawn smaller audiences. Then again, ratings were not really the problem. Dozens of advertisers pulled out of “The O’Reilly Factor.” It doesn’t matter how many people tune in, if companies refuse to book commercials.

Besides principles of right and wrong, which are not always paramount in business, there was Fox News’s brand image to consider. Sexual harassment allegations pushed out Ailes, and with similar accusations dogging O’Reilly, the network appeared hostile to women.

A company’s reputation is a difficult thing to quantify, but consider this, from the Department of Anecdotal Evidence: As of Monday, the Fox affiliate in Boston, the nation’s ninth-largest media market, will change the name of its local newscast from “Fox 25 News” to “Boston 25 News” because it considers the Fox brand a liability.

So far, Fox News has marched on — seemingly as strong as ever — without Ailes, Van Susteren and Kelly. As the network prepares for a future without O’Reilly, the question is whether its most popular host is similarly expendable or uncommonly difficult to replace.